There are nearly one million persons living with confirmed HIV infection (PLWH) in the US, 60% of them smoke cigarettes, and 75% of them are interested in quitting. Almost none are currently accessing smoking cessation interventions designed to meet their specific needs and concerns. Cigarette smoking is a leading contributor to mortality among PLWH in the HAART era, and it is the direct cause of 30% of non-AIDS defining malignancies. It is driving the alarming rise in cardiac events and lung cancers in this highly vulnerable population. The lack of access to proven, effective, culturally appropriate tobacco cessation services represents a health disparity of the first order. The psychosocial profile of the PLWH-smoker community, characterized by high rates of psychiatric comorbidity, drug and alcohol use, and low levels of social support, suggests that achieving high cessation rates will be a great challenge. Positively Smoke Free is an intensive, multisession, cessation intervention specifically developed for PLWH smokers. It is currently available as a live, group therapy program and also as a web-based version designed for notebook or desktop computers. In its current form, the web-version is not adoptable to the smartphone platform. Pilot data from randomized, controlled, trials of both formats show promise. The number of individuals in the US who own smartphones and who use them to access health information on the internet is steadily growing. This growth is most pronounced in the ethnic minority groups that make up the majority of the PLWH community in the US. Behavioral interventions delivered via smartphones offer the advantage of expansive reach, low cost, and immediacy of access to users. A burgeoning body of literature suggests that this may be an especially effective tool for tobacco treatment. mHealth tobacco treatment interventions for PLWH smokers have not yet been explored. This proposal aims (1) to adapt Positively Smoke Free to the mobile format for smartphones (2) to test the feasibility (i.e. recruitment, adherence, retention, satisfaction, and cost) of mobile Positively Smoke Free (mPSF) in a cohort of 50 PLWH smokers, (3) to complete a pilot randomized controlled trial comparing biochemically confirmed 3-month abstinence rates in subjects (N=50) assigned to the mPSF condition versus those (N=50) assigned to standard care (all subjects will be offered a 3-month supply of nicotine replacement therapy) and (4) to conduct exploratory analyses of putative moderators and mediators of program efficacy. If the mobile version of PSF is proven to be feasible and efficacious, the project will have short term impact by opening a new vista of tobacco (and other behavioral) treatment for a highly vulnerable group. Study data will provide crucial information for a definitive trial of the intervention. The long-term impact will be reduced tobacco-related morbidity and mortality among PLWH, and a clearer understanding of the role of mHealth in comprehensive HIV care.